Political rights and civil liberties in South Korea are on a downward trend, a U.S. rights group said Wednesday, citing what it described as "crackdowns on public criticism" of the government following the Sewol ferry disaster.

In its "Freedom in the World 2015" report, Freedom House classified South Korea as a free country with two points on a one-to-seven scale in both the political rights and the civil liberties categories. The lower the score, the more rights are guaranteed.

But the group put South Korea among 19 countries that are on a downward trend in their rights situations.

"South Korea received a downward trend arrow due to the increased intimidation of political opponents of President Park Geun-hye and crackdowns on public criticism of her performance following the Sewol ferry accident," the group said.

After the Sewol ferry accident and related criticism and rumors surrounding the president, the government began routine monitoring and censorship of online discussions, the report said.

North Korea received the lowest score of 7 in both categories, along with Sudan and Syria. (Yonhap)